Add the ability to write comments in a solution (.sln) file

I think it would be beneficial to allow for comments in a solution file, since not all solution files are generated/managed by an IDE, but directly edited in a text editor. There are articles/comments online that say the # character is used for comments, but that’s not quite how the solution file is processed by msbuild:

https://github.com/microsoft/msbuild/blob/0f3d8e94ac11dd892c0c2fadb28b1a42e0d45fb1/src/Build/Construction/Solution/SolutionFile.cs#L435-L462

EDIT: Removed ambiguous references and other formatting.

[alanta]

Another use case for this is to allow excluding parts of a .sln file in a dotnet new template. For example:

#if (includedatabase)
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microservice.Database", "Microservice.Database\Microservice.Database.csproj", "{6F650E2B-8E2C-414A-A5CA-6B983B39746B}"
EndProject
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microservice.Database.Migrations", "Microservice.Database.Migrations\Microservice.Database.Migrations.csproj", "{51DCC1F2-D929-429C-80AD-F446C8386CE1}"
EndProject
#endif

This is part of a solution file that’s packaged up into a template and processed when the package is newed up. The comments are processing instructions for dotnet new.
To verify the solution before packaging I tried to build it, but after adding these comments the solution no longer builds from the CLI (.NET Core 3.0 preview 6). I can load it in Visual Studio 2019 without problems though.

[simplexidev]

Which works only for top-level elements. If Visual Studio’s solution parser handles comment lines elsewhere, MSBuild’s should too.

My main use case for this is to separate the ProjectConfigurationPlatforms in the global sections, so it’s easier to see what is what when you have numerous projects in a solution, so top-level comments don’t really help in that situation.

EDIT: I don’t know if VS’s parser handles comments, but i agree that the implementations should parse two identical files the same, comments or not.